#!/usr/bin/python2.7
import math
def quadratic_equation(a, b, c):
	de = b ** 2 - 4 * a * c
	if de >= 0:
		x1 = (-b + math.sqrt(de)) / ( 2 * a )
		x2 = (-b + math.sqrt(de)) / ( 2 * a )
		return x1, x2
	else:
		return
print quadratic_equation(2, 3, 0)
print quadratic_equation(1, -6, 5)
